1. Field of the Invention
The present invention relates to a medium frequency x-ray generator, and in particular to a portable medium frequency x-ray generator.
2. Description of the Prior Art
In an x-ray diagnostics generator, the maximum power of the tube depends upon the internal resistance seen by the x-ray tube, which includes the internal resistance of the generator itself as well as the internal resistance of the power supply. For stationary generators, the value of the internal resistance can be easily determined because the generator is always connected to the same power source, and thus the internal resistance of the power source will not vary, i.e., the power source internal resistance is known. The maximum x-ray tube power can then be adjusted dependent upon this fixed internal resistance.
For portable x-ray diagnostics generators, in contrast, the internal network resistance may differ from plug to plug. If the x-ray tube power is matched to a highest occurring internal network resistance, the exposure time will be unnecessarily long when the generator is connected to networks having a lower internal resistance, because the x-ray tube current could be higher in such cases than when the generator is connected to a highest internal network resistance. If one generally employs a high x-ray tube power, the x-ray tube voltage may fall in an undesired manner when the generator is connected to poor networks.